1. Field of Invention
The invention relates to a method for producing a light emitting diode (LED) support structure and, in particular, to a method of producing an electro-thermal separation type LED support structure. A heat dissipation plate and a support plate are coupled to form at least two heat dissipation bases and at least two conductive supports. Alternatively, a thick-thin plate is used to form at least two heat dissipation bases and at least two conductive supports. The LED chips of different types are configured on the heat dissipation bases, respectively.
2. Related Art
In recent years, the LED has become very popular for the indicators on information or communications devices and display devices. This is because it has the features of low power consumption, long lifetime, virtually no warm-up time, and fast reactions. Moreover, it has a small volume and is vibration-resistant, ideal for mass production. Therefore, they are widely used as the backlight source of mobile phones and personal digital assistants (PDA's), various outdoor displayers, traffic lights, and vehicle lights.
Normally, the LED chip is fixed onto a support in a plastic base with a concave part via a Surface Mount Device (SMD) or flip chip bonding. FIG. 1 is a side cross-sectional view of the LED chip with a first conventional LED support structure.
The plastic base 81 with a concave part 82 is embedded with at least two supports 83. Part of each support 83 is exposed in the concave part 82 of the plastic base 81. Part of each support 83 extends out of both sides of the plastic base 81 to form electrical connection parts 84 in order to electrically connect to other electronic devices (not shown).
Afterwards, the SMD is used to fix the LED chip 85 on one of the supports 83 in the concave part 82 of the plastic base 81. Wire bonding or flip chip bonding is then employed to electrically connect the LED chip 85 with the other support 83 via a wire 86. Finally, the concave part 82 of the plastic base 81 is filled with packaging plastic 87, thereby covering the LED chip 85 and the supports 83 in the concave part 82.
However, heat dissipation of the LED chip 85 in the above-mentioned LED support structure is via the supports 83 connected to the LED chip 85. At the same time, the supports 83 serve the function of electrical connection for the LED chip 85. Therefore, the supports 83 have lower heat dissipation efficiency for the LED chip 85. This method is thus not suitable for high-power LED chips 85.
A new electro-thermal separation type LED support structure has been proposed, as shown in FIG. 2. FIG. 2 is a top view of the LED chip with a second conventional LED support structure.
In this embodiment, the plastic base 81 with a concave part 82 is embedded with a heat dissipation base 88 and at least two supports 83. Part of the heat dissipation base 88 and each support 83 is exposed in the concave part 82 of the plastic base 81. Part of each support 83 extends out of both sides of the plastic base 81 to form electrical connection parts 84 for electrical connections with other electronic devices (not shown).
Afterwards, the SMD is used to fix the LED chip 85 on the heat dissipation base 88 in the concave part 82 of the plastic base 81. Wire bonding or flip chip bonding is employed to electrically connect the LED chip 85 with the supports 83 via wires 86. Finally, the concave part 82 of the plastic base 81 is filled with packaging glue 87 to cover the LED chip 85 therein, the heat dissipation base 88, and the supports 83.
Embedding the heat dissipation base 88 and the supports 83 in the plastic base 81 can effectively dissipate heat of the LED chip 85 while achieving the electrical separation design. The heat dissipation base 88 embedded in the plastic base 81 dissipates heat produced by the LED chip 85. The supports 83 embedded in the plastic base 81 provide electrical connections for the LED chip 85. This method enhances heat dissipation efficiency of the LED chip 85. Therefore, it solves the problem in the first conventional LED support structure.
However, since the second conventional LED support structure only embeds one heat dissipation base 88 in the plastic base, one has to use LED chips 85 of the same type (PNP or NPN) when several of them are configured on the heat dissipation base 88. That is, only LED chips 85 of the same type can be simultaneously configured on the heat dissipation base 88. This is a restriction to the use and electrical connection of the LED chip 85.
In summary, the prior art always has the problem that only LED chips of the same type can be used on the heat dissipation base. It is therefore desirable to provide a solution to remove such a constraint.